The present invention relates generally to microelectromechanical systems (MEMS), and in particular to techniques for fluid delivery in applications involving nanometer-scale operations, such as assays and/or amplification and subsequent modification of DNA in biochips. In addition this invention can be used to remove or add material via chemical, electrochemical, biochemical, mechanical and electrical methods in small controlled regions down to atomic dimensions of 0.1 nanometer.
Nanometer-scale components find utility in a wide variety of fields, particularly in the fabrication of microelectromechanical systems (MEMS). Typical MEMS include microsensors, micro-actuators, micro-instruments, micro-optics, and the like. Nanotechnology refers to broad categories of nanometer-scale manufacturing processes, materials and devices, including, for example, nanometer-scale lithography and nanometer-scale information storage. Many MEMS fabrication processes exist, including, for example surface micromachining techniques. Surface micromachining involves fabrication of microelectromechanical systems from films deposited on the surface of a substrate. For example, a common fabrication process includes depositing thin layers of polysilicon on a sacrificial layer of silicon dioxide formed on a bulk silicon substrate. Controlled removal of the selected portions of the various layers of material can produce useful micro- and nano-scale machine components.
Conventional semiconductor processing typically is performed in vacuum. The nature of the surrounding ambient is important. Often a dry ambient is required to avoid oxidizing and otherwise contaminating the surface of the silicon surface. Presently static conditions, vacuum generation, moisture problems and/or chemical reactivity control is obtained in SPM (scanning probe microscopy) systems and nanomachining centers by the introduction of large quantities of gas (including CDA, clean dry air) at some distance many inches or more away from the probe subject site. These gross-scale manipulations of fluid are at odds with the fine-scale operations required in nanotechnology-based machining systems. To date, no suitable techniques exist to provide for more effective gas and vacuum delivery in the proximity of a site being worked by a nanomachining process.